The present invention relates generally to angiography and deals more particularly with marking devices used for the fluoroscopic localization of coronary grafts.
The coronary artery bypass operative technique wherein a vein or other suitable conductor is grafted between the ascending aorta and the coronary arteries has been increasingly used in the repair and treatment of diseased hearts and associated blood carrying vessels to bypass and/or remove blockages which produce angina. Although the bypass operative technique is generally successful in the treatment of blockages associated with heart vessels, it has been observed that the bypass grafts do not always remain open. Consequently, the patency of coronary bypass grafts must often be monitored and evaluated in post-bypass patients.
An angiographic procedure which permits the roentgenographic visualization of a blood vessel that has been injected with a radiopaque substance is generally utilized by a cardiologist and a cardiovascular surgeon to assess the condition of the blood vessel being evaluated. The angiographic procedure which generally requires the insertion of a catheter into the vascular system, generally entering through the arm or groin area, to locate the opening of a bypass graft for injection of a radiopaque dye is generally very time consuming and difficult because there are no standard locations for coronary grafts. Therefore, the cardiologist must feel via the catheter the entire inner surface area of the ascending aorta for the dimple or notch present at a graft orifice. The hit or miss procedure in locating the coronary grafts can have the result that a graft not located may be mistakenly concluded to be blocked rather than missed. The cardiologist may make several angiographic dye injections in repeated attempts to locate the missing graft. The repeated attempts to locate missing grafts can be life threatening to the patient because the repeated dye injections place further burdens on the heart and each injection is accompanied by additional radiation exposure. In addition, the repeated attempts to locate missing grafts expose the cardiologist and the staff performing the angiographic procedure to dangerous radiation as well.
It is desirable therefore to have a coronary graft marker to aid in the localization of a coronary graft during catherization, minimize the time required to perform the angiographic procedure and reduce exposure to radiation.
Coronary graft markers are applied during coronary bypass surgery and provide a radiographic guide to improve localization of the graft during catherization. There are a number of currently available coronary graft markers, however, these markers are not entirely satisfactory and have significant short comings.
One currently available coronary graft marker requires the suturing of a steel or similar material washer to the aorta next to the anastomosis. Since the washer may be located at any point next to the anastomosis and not around it, localization is only approximate and actual usefulness during the angiographic procedure is limited.
Another problem associated with the washer marker is the requirement of suturing to the aorta. Each stitch during the operative procedure requires additional time and increases the risk of bleeding from the aorta or disruption of the anastomosis.
A further problem associcated with the washer marker is that if the anastomosis requires further attention during the operative procedure, the washer may impede access to the suture line joining the vein to the aorta.
An additional problem associated with the washer marker is that the rigidity of the marker may cause it to impinge on the anastomosis.
Yet an additional problem associated with the washer marker is that if a reoperation is required the rigid washer may impair the dissection and clamping of the aorta.
Another currently available coronary graft marker which overcomes some of the limitations of the washer marker is a semi-rigid steel ring which is opened, placed around the anastomosis, closed and sutured in place to the aorta. Because the ring surrounds the anastomosis, the accuracy problem associated with the localization of a coronary graft is overcome. Although the steel ring coronary graft marker overcomes the localization problem, it is characterized by additional problems and limitations.
One major problem associated with the steel ring marker is that since the ring surrounds the anastomosis, it may impinge on the graft and impair patency.
Another problem associated with the steel ring marker is the requirement of suturing to the aorta. As with the washer marker, additional time is required during the operative procedure to suture the ring to the aorta and each stitch increases the risk of bleeding from the aorta or disruption of the anastomosis. Additionally, because the ring surrounds the anastomosis a number of sutures may be required to position and maintain the ring in place to keep it from impinging on the graft.
A further problem associated with the steel ring marker is that if the anastomosis requires further attention during the operative procedure, the ring may impede access to the suture line.
An additional problem associated with the steel ring marker is that if reoperation is required, the size and bulk of the ring can seriously impair the dissection and clamping of the ascending aorta.
A general aim of the invention is therefore to provide a coronary graft marker that permits the accurate localization of a coronary graft during catherization, with a further aim being to provide such a coronary graft marker that does not require suturing to the aorta thereby minimizing the risk of bleeding and disturbance to the anastomosis.
These general aims are achieved in accordance with the invention and as described in more detail hereinafter, by a sutureless, anastomotic coronary graft marking device having radiopaque indicators attached to an absorbable hemostatic material sheet so that the indicators encircle the grafted artery and become attached to and held in place by fibrous tissues of the body without impinging on or interfering with the anastomosis.
Other objects and advantages of the invention will be readily apparent from the following detailed description and from the accompanying drawings forming a part thereof.